Osmometric heart monitoring device and methods

• US 7,734,349 B2
• Filed: 07/18/2007
• Issued: 06/08/2010
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Qu, Jihong, Mokelke, Eric A., Kane, Michael John, Shuros, Allan Charles
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Kimball; Jeremiah T
• Application Number:
  US11/779,403
• Publication Number:
  US 20090024177A1
• Time in Patent Office: 1,056 Days
• Field of Search: 607/22
• US Class Current: 607/22
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: G01N 13/04 Investigating osmotic effects

Abstract

Embodiments of the invention are related to monitoring devices and methods with osmometric sensors, amongst other things. In an embodiment, the invention includes an implantable heart failure monitoring system including an osmometric sensor, the osmometric sensor configured to generate a signal corresponding to the osmotic strength of a bodily fluid, and a controller in communication with the osmometric sensor, the controller configured to receive and process the signal corresponding to the osmotic strength of a bodily fluid. Other aspects and embodiments are provided herein.

Claims

1. An implantable osmotic heart monitoring system comprising:

an osmotic pH sensor, the osmotic pH sensor configured to generate a signal corresponding to pH of a bodily fluid, the osmotic pH sensor comprising a wall member defining an enclosed volume, the wall member comprising a semi-permeable membrane; and

a solution comprising a solvent and a solute, the solution disposed within the enclosed volume, the solute configured to change osmotic strength in a pH range of between about 7.3 and about 7.5, and the solute having a pKa of between about 6.0 and about 10.0;

the semi-permeable membrane permeable to the solvent and impermeable to the solute; and

a controller in communication with the osmotic pH sensor.

2. The implantable osmotic heart monitoring system of claim 1, the controller configured to generate a warning notification if the pH falls below a preselected threshold level.

3. The implantable osmotic heart monitoring system of claim 1, further comprising a lead comprising a lead body and a conductor disposed within the lead body, the conductor in electrical communication with the osmotic pH sensor and the controller.

4. The implantable osmotic heart monitoring system of claim 3, the osmotic pH sensor disposed on the lead body.

5. The implantable osmotic heart monitoring system of claim 4, the lead further comprising an electrode configured to interface with a target tissue.

6. The implantable osmotic heart monitoring system of claim 5, the controller further configured to generate electrical stimulation pulses to be delivered to the target tissue though the electrode.

7. The implantable osmotic heart monitoring system of claim 2, the preselected threshold level comprising a pH of 7.3.

8. The implantable osmotic heart monitoring system of claim 1, further comprising a first pressure sensor configured to sense the pressure within the enclosed volume.

9. The implantable osmotic heart monitoring system of claim 8, further comprising a second pressure sensor configured to sense the pressure outside of the enclosed volume.

10. The implantable osmotic heart monitoring system of claim 1, the semi-permeable membrane comprising a biocompatible material.

11. The implantable osmotic heart monitoring system of claim 1, the semi-permeable membrane having a thickness between about 1 nanometer and about 2 millimeters.

12. The implantable osmotic heart monitoring system of claim 1, the semi-permeable membrane comprising a polymer.

13. The implantable osmotic heart monitoring system of claim 12, the polymer comprising polytetrafluorethylene.

14. The implantable osmotic heart monitoring system of claim 1, the controller comprising a microprocessor.

15. The implantable osmotic heart monitoring system of claim 1, the solution disposed within the enclosed volume having a starting osmotic strength of between about 280 and 303 mOsm per kg.

16. The implantable osmotic heart monitoring system of claim 1, further including a housing and a header assembly, the osmotic pH sensor disposed on the housing.

17. The implantable osmotic heart monitoring system of claim 1, the solute comprising an acid salt.

18. The implantable osmotic heart monitoring system of claim 8, the first pressure sensor comprising an electrical pressure sensor.

19. The implantable osmotic heart monitoring system of claim 9, the second pressure sensor comprising an electrical pressure sensor.

20. The implantable osmotic heart monitoring system of claim 1, wherein the system is configured to modulate a minimum cardiac pacing rate based on the signal generated by the osmotic pH sensor.